Re: [meteorite-list] NASA Spacecraft En Route to Pluto Prepares for
Thanks Rob (from another Rob). Your explanation was very concise and clear. Especially having just read Ron's reply. As I told Ron, I'm going to have to spend some time daydreaming about it to get it comfortable in my head but I at least understand the physics now. There was me thinking it may have something to do with general relativity. I always doubted this because of the low masses and velocites involved. As for Isaac Newton, I still think he'd be grumpy about it all. His equations are only really much good in a 2 body situation. As I understand it, 3 bodies are a nightmare and ultimately unpredictable, though I don't know why, exactly. Once again, wonderful answers to my questions. I can go to bed now, content that I am a little smarter than when I woke up. Rob McC Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. http://autos.yahoo.com/new_cars.html __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] NASA Spacecraft En Route to Pluto Prepares for
Oh, great question and answer. Thanks Rob and Ron and Robert!! Jerry Flaherty - Original Message - From: "Ron Baalke" <[EMAIL PROTECTED]> To: "Meteorite Mailing List" Sent: Thursday, January 18, 2007 5:55 PM Subject: Re: [meteorite-list] NASA Spacecraft En Route to Pluto Prepares for > >> >> Could someone clarify something which ahs been >> bothering me for years about this gravity assist >> technique? >> >> Why does the spacecraft come out of the gravity well >> going faster than it went in without thrust? >> >> Why does this not apply to spacecraft? > > It does apply. Gravity assists always involve 3 bodies, > and the relative velocities to each other. > In this case, the three bodies are the spacecraft, > Jupiter and Sun. After New Horizons flies by Jupiter, > there is no velocity change RELATIVE TO JUPITER. > But the spacecraft does pick up extra velocity RELATIVE > TO THE SUN. In return, Jupiter will slow down RELATIVE > TO THE SUN. The velocity changes RELATIVE TO THE SUN > are related to their respective masses. Since the > spacecraft is so much smaller in mass than Jupiter, > the velocity increase for the spacecraft is rather > substantial. Jupiter's slowdown will be very > miniscule because of its larger mass. > > Make sense now? > > Ron Baalke > __ > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] NASA Spacecraft En Route to Pluto Prepares for
> > Could someone clarify something which ahs been > bothering me for years about this gravity assist > technique? > > Why does the spacecraft come out of the gravity well > going faster than it went in without thrust? > > Why does this not apply to spacecraft? It does apply. Gravity assists always involve 3 bodies, and the relative velocities to each other. In this case, the three bodies are the spacecraft, Jupiter and Sun. After New Horizons flies by Jupiter, there is no velocity change RELATIVE TO JUPITER. But the spacecraft does pick up extra velocity RELATIVE TO THE SUN. In return, Jupiter will slow down RELATIVE TO THE SUN. The velocity changes RELATIVE TO THE SUN are related to their respective masses. Since the spacecraft is so much smaller in mass than Jupiter, the velocity increase for the spacecraft is rather substantial. Jupiter's slowdown will be very miniscule because of its larger mass. Make sense now? Ron Baalke __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] NASA Spacecraft En Route to Pluto Prepares for Jupiter Encounter
Jupiter's > gravity will > accelerate New Horizons away from the sun by an > additional 9,000 > miles per hour, pushing it past 52,000 mph and > hurling it toward a > pass through the Pluto system in July 2015. > Could someone clarify something which ahs been bothering me for years about this gravity assist technique? Why does the spacecraft come out of the gravity well going faster than it went in without thrust? You remember the conservation of energy stuff from school? GravPotential to Kinetic to GravPotential. A ball rolling down a hill can only roll up the other side to a height as high as it was released from. Why does this not apply to spacecraft? It's climbing out of the suns gravity well so it ought to be slowing down all the way. When you drop into Jupiters gravity well I can see that you're going to speed up but on the way out surely it'll lose all that speed and at the end of the encounter should be no faster than it went in at. In fact, slower because it's now further up the hill of the suns gravity well. Please, will someone tell me what I'm missing. It bothers me tremendously that I have a BSc in physics and studied both astronomy and astrophysics subsids and I don't get it. It's the same with asteroids getting ejected into orbits further out. How? How? Sir Isaac would not be amused Rob McC Looking for earth-friendly autos? Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center. http://autos.yahoo.com/green_center/ __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
